import 'package:flutter/material.dart';

class ChildCase extends StatefulWidget {
  const ChildCase({Key? key, required this.count, required this.updateCallBack})
      : super(key: key);

  final int count;

  final Function(int) updateCallBack; // 接收一个回调函数

  @override
  _ChildCaseState createState() => _ChildCaseState();
}

class _ChildCaseState extends State<ChildCase> {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        Text(
          "父组件传递过来的值: ${widget.count}",
          style: TextStyle(color: Colors.red, fontSize: 30),
        ),
        ElevatedButton(
            onPressed: () {
              // 实现子传父
              //  widget.count+1 // 子传父
              widget.updateCallBack(widget.count + 1);
            },
            child: Text("修改值"))
      ],
    );
  }
}


// updateValue: (count: number) => void = () => {} 